An alkaline battery (silver oxide battery) includes a positive electrode containing a silver oxide, a negative electrode containing zinc or zinc alloy, and an alkaline electrolyte solution. This alkaline battery has been widely and generally used as a primary battery.
On the other hand, the alkaline battery having the above configuration has also been studied for use as a secondary battery (see Patent Document 1).
However, when the alkaline battery having the above configuration is repeatedly charged and discharged, the battery capacity can be sharply reduced with only a small number of repetitions. This may be attributed to the negative electrode. For example, zinc dendrite grows from the negative electrode and extends to the opposite electrode, which will cause an internal short circuit.
To deal with this problem, when zinc is contained in a negative electrode of a secondary battery, a technique has been proposed to add calcium hydroxide to the negative electrode so that the precipitation of zinc dendrite is reduced (see Patent Documents 2 and 3).
Similarly, a technique has been proposed to add an organic matter with a particular structure to an electrolyte (electrolyte solution) so that the precipitation of zinc dendrite is reduced (see Patent Document 4).
Moreover, Patent Documents 5 and 6 have proposed the use of an anion conducting material in a separator or an electrolyte of an alkaline battery to improve the cycle life of the alkaline battery. The anion conducting material is formed by incorporating various metal compounds in a polymer that serves as a matrix.